Die structure for bending sheet metal



D R O F w A R C E DIE STRUCTURE FOR BENDING- SHEET METAL Dec 2 sheetswsht l IIIIIIIII Y L V I Ewan? ra ra Patented Aug. 13, 1946 UNETED STATESPATENT OFFICE DIE STRUCTURE FOR BENDING SHEET METAL Francis Crawford,Scarsdale, N. Y. Application December 8, 1943, Serial No. 513,331

10 Claims.

while avoiding undesirable lateral shifting of the sheet metalregardless of face contour thereof during the bending operations.

A more specific object is the provision of a simple and effective maledie structure which includes a plurality of prick-punches extending arelatively short distance from the working surface to be engaged intothe stock of the sheet metal accurately to hold it in position as a bendis died therein, and'its combination with cooperating female diestructure.

Another object of the invention is to provide such die structure wherebyin the formation of bent sheet metal articles necessity forpreliminarily cutting stock oversize, then bending and finally trimmingto dimension resulting-in loss of material is efficiently eliminated.

Still another object of the invention is the provision of such male diestructure wherein a plurality of sockets are provided removably toreceive alternatively prick-punches and properly shaped plugs to permitemployment at will of as few or as many work-locating prick-punches andany specific arrangement thereof as may be dic tated by a particular jobwhile assuring smooth substantially continuing working surfaces atsockets where the employment of prick-punches is not desired.

An additional object of the invention is the provision of structuralembodiments of the apparatus which are readily constructed and alloweflicient use and operation thereof.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the features of construction,combination of elements and arrangement of parts, which will beexemplified in the construction hereinafter set forth and the scope ofthe invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

different known types of embossed floor plate stock which may beaccurately bent with the employment of die structure of the presentinvention;

Figs. 2 and 4 are sectional elevations of the embossed floor platestocks shown respectively in Figs. 1 and 3, with Fig. 2 taken on line 22of Fig. 1 and Fig. 4 taken on line 4-4 of Fig. 3;

Fig. 5 is an elevational sectional View of male and female die structureof the present invention 7 showing in section a piece of embossed floorplate Fig. 1 and 3 are top plan fragmentary views of 55 heldtherebetween in a predetermined position for the accurate formation of abend in the plate; Fig. 6 is a side elevational view of the structureshown in Fig. 5, with parts of the dies broken away and showing thepiece of floor plate sectioned along the line on which it is to be bent;

Fig. '7 is an end elevational view of die structure similar to thatshown in Figs. 5 and 6, showing in section a piece of embossed floorplate to be bent located between the dies in reversed position; and IFig. 8 is a side elevational view, with parts broken away, of the diestructure shown in Fig. 7,

showing the floor plate sectioned along the line, such as line M of Fig.3, on which it is to be bent.

Prior to the present invention it has been deemed by those skilled inthe art of handling and bending embossed floor plate stock to beimpractical or impossible to cut the stock to accurate dimensions andthen to form a desired bend in the accurately dimensioned pieces along apredetermined line. the fact that in many designs of embossed floorplates the patterns of the bosses thereof cause differingcross-sectional areas or thicknesses along different vertical planes.This is true of the two well known types of embossed floor plates shownin Figs. 1 to 4, inclusive, wherein in Figs. 1 and 2 the Diamonette andin Figs. 3 and 4 the Waffle" patterns are respectively indicated. Itwill readily be seen from an inspection of these figures that theDiamonette plate It and the Waffle plate 1 l are Weaker along planesbetween adjacent rows of their respective bosses I 2.-|2 and. i3-I3..Thus in attempting to bend such stock between male and female diesthere is a tendency for plates thereof to shift laterally to a line ofleast resistance, or for sloping faces of the bosses when brought intocontact with'anangularly disposed face of the male die structure tocause a lateral shifting away from the line along This is at leastpartially due to able that it has given rise to a common practice in theart of first forming a desired bend in an oversized piece of theembossed stock and then trimming the resulting bent piece to dimension.This, of course, causes undesirable wastage of material and furtherincreased costs due to additional trimming operations required. Theseand other difiiculties of the prior art are efiiciently eliminated bythe present invention.

In the drawings like numerals identify similar parts throughout. Inaccordance with one em bodiment of the invention disclosed in Figs. 5and 6, the die structure preferablycompiises a female die l5 having anelongated groove 36 formed in its face which groove by way of example,for the formation of a substantially sharp bend such as at a rightangle, is V-shaped as shown. A male die I! i provided to cooperate withthe female die l5 and it has a complementary elongated ridge 18 tocooperate with the groove l6 for the formation of a bend along dot-dashline H), for example, inapiece of embossed floor plate 18.

In order to avoid lateral shifting of the piece of embossed floor platestock, or other sheet metal stock, when the female and male dies i5 andH are caused to approach each other, a plurality of prick-punches 2il2ilprojecting a relatively short distance from the surfaceof the ridge [8are employed. This is preferably accomplished by providing a pluralityof cylindrical socket 2 2i along the edge of the ridge l8 removably toreceive therein cylindrical, pointed prick-punches, preferably formedfrom specially treated hardened steel. It is particularly desirable thatthe prick-punches 29-49 be of such longitudinal dimension asto projectfrom or beyond the surfaces of the ridge 18 only a limited distance sothat they will not pierce entirely-through the sheet metal stock orembossed floor plate. The prick-punches are employed merely to pierceinto the surface of thesheet metal stock or steel floor platesufficiently to anchor the plate in position to prevent the' latter fromslipping or shifting laterally during bending operations.

The number of prick-punches 21B-20which' are employed may vary'inaccordance with the dietates of a particular job or the result desired.Accordingly, prick pun'chesare removably mountedinthe sockets 2 1-2 iwith'rathera tightfit to assure their remaining in proper positionduring operation of the die structure. Removal of the prick-punches20'-28' is provided for by a plurality of knock-out holes' -22'-22 eachof which extendsthrough the body of the male diel'l' from the baseportion 23 thereof to. one of the Sockets 2!: so that a driving'rod maybe received therein. The'number'of prick-punches'is determinable by theallowable-tolerances in bending a particular sh'eetmetal stock. The morepunche employed the more accurate will be bends formed by the diestructure. It hasbeen found to be desirable to provide a wide male diewith a plurality of sockets located at'intervals of about three inches.This will assure the provision of as many prickpunchesas will probablybe found to be desirable for any particular job demanding the employmentof a maximum-number thereof.

However, the fewer the number of prickpunches which. can beemployedwhile still assuringsuflicient accuracy ofbend for a particularjob; thatis, with-aparticular type of sheet metal stock; themoresatisfactory may be the results sinceithere will'be' less tendencyfor weakening of thestock along bend: lines, less surfacemarring, etc.Therefore, it is desired that as few iii punches as it is convenientlypossible to use on a particular job be employed but that, whenprick-punches are omitted from certain sockets, those blank sockets donot present sharp edges or deforming surfaces which might tend to marthe work and that there be no void space in the die stock along workingsurfaces. Accordingly a plurality of plugs, such as shown at 24 in Fig.6, are provided, each of which is removablyreceivable in one of thesockets and when so seated has its exposed end contoured similarly tothe contour of the face of the male die to provide a substantiallyunbroken working surface. These plugs 24-44 are preferably formed ofmaterial similar to that employed in the construction of the male die H,such as steel.

It is frequently desirable to reverse the em.- bossed fioor plate whenit is positioned between the dies, that is, with the substantially flatbottom face thereof positioned adjacent the male die, as shown in Figs.'7 and 8. In those figures a typical embodiment of the invention, whichhas been constructed and is now in commercial use, has been shownapproximately to scale. It is in dicated therein that the prick-punches29-20 extend from the edge of the bending ridge I8 less than thethickness of the base of the plate stock. For example, for one-eighthinch embossed steel floor plate stock the prick-punches preferablyextend about three thirty-seconds of an inch, so that should anyprick-punch chance to be located between bosses where the stock isthinnest, such as at 25, the prick-punch will not pierce through. Anadvantage of this positioning of the floor plate stock between the diesis that when the prick-punches 20- 20 first engage the floor plate a thedies are caused to approach each other there are noboss sloping surfacesto be engaged by the tapered points of the prick-punches which might insome cases tend to cam the plate sideways for lateral shifting thereof.Of course the position of the floor plate stock between the diesfrequently will be dictated by the direction in which the bend or bendsis or are to be made for a particular job. Where the edge of a stairtread is to be turned down to overlie the riser the plate will bebent inaccordance withthe teaching of Figs. 7 and 8, but should it be desiredto bend the other edge of the plate upwardly to overlie the succeedingriser then the other procedure proposed in Figs. 5'and 6 will beemployed to perform suchbend.

The present invention has in actual commer cial operations proven to beof great importance in the art of bending embossed floor plate stock andunexpectedly to accomplish desired ends which previously had beenthought by those skilled in the art of bending and handling embossedfloor plate stock'to be'impossible of attainment. The inventioneliminates the necessity of precutting pieces of stock to oversizedimensions, then bending them and finally trimming to actual dimensionswith reference to a bend or bends formed as an intermediate step orsteps.

It will thus be seen. that the objects set forth above among others are'efii'ciently attained and since certain changes may be made in theabove construction and different embodiments of the invention could bemad without departing from the scope thereof, it is intended'that allmatter' contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

It is also to be understood that the following claims are intended tocover all of: the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent is: 1. Dies for bending sheet metal of a certainminimum over-all thickness, and the like, comprising, in combination, afemale die having an elongated V-shaped groove in its face, a male diecomprising a substantially solid relatively unyielding body having acomplementary elongated V- shaped ridge to cooperate with the groove,and a plurality of localized prick-punches projecting a relatively shortdistance from and beyond all portions of the edge of said V-shaped ridgeand substantially less than the mentioned minimum thickness of the sheetmetal to be bent to pierce into a surface of the sheet metal withoutperforating it to hold it securely in predetermined position as the diesare brought together to assure accurate location of a bend, thoseportions of the surface of said ridge intervening said prosocketsprojecting a relatively short distance from the surface of said ridgeand substantially less than the mentioned minimum thickness of the sheetmetal to be bent to pierce into a surface of the sheet metal withoutperforating it to hold it securely in predetermined position as the diesare brought together to assure accurate location of a bend.

3. Dies for bending sheet metal of a certain minimum over-all thickness,and the like, comprising, in combination, a female die having anelongated groove in its face, a male die having a complementaryelongated ridge to cooperate with the groove, said male die having aplurality of sockets in the face of said ridge arranged along theportion thereof which is farthest from the base of said ridge, aplurality of prick-punches removably seated in at least some of thesockets projecting a relatively short distance from the surface of saidridge and substantially less than the mentioned minimum thickness of thesheet metal to be bent to pierce into a surface of the sheet metalwithout perforating it to hold it securely in predetermined position asthe dies are brought together to assure accurate location of a bend, andat least one plug remcvably seated in one of the sockets having itsexposed end contoured similarly to the contour of the face of said ridgeto provide a substantially unbroken Working surface.

4. Dies for bending sheet metal of a certain minimum over-all thickness,and the like, comprising, in combination, a female die having anelongated V-shaped groove in its face, a male die having a complementaryelongated V-shaped ridge to cooperate with the groove, said male diehaving a plurality of sockets in the edge of said V-shaped ridge. aplurality of prick-punches removably seated in at least some of thesockets projecting a relatively short distanc from the edge of saidV-shaped ridge and substantially less than the mentioned minimumthickness of the sheet metal to be bent to pierce into a surface of thesheet metal without perforating it to hold it securely in predeterminedposition as the dies are brought together to assure accurate location ofa bend, and at least one plug removably seated in one of the socketshaving its exposed end contoured similarly to the contour of the edge ofsaid ridge to, provide a substantially unbroken Working surface. 7

5. A male die for cooperation with a female die to bend sheet metal of acertain minimum overall thickness, and the like, comprising an elongatedridge providing a Working face and having a plurality of sockets thereinarranged along the portion thereof which is farthest from the base ofsaid ridge, and a plurality of prickpunches removably seated in at leastsome of the sockets projecting a relatively short distance from theworking surface of said ridge and substantially less than the mentionedminimum thickness of the sheet metal to be bent to pierce into a surfaceof the sheet metal without perforating it to hold it securely inpredetermined position during theformation ofa bend therein.

6. A male die for cooperation with a female die to bend sheet metal of acertain minimum over-all thickness, and the like, comprising anelongated V-shaped ridge providing a working face and having a pluralityof sockets therein arranged along the portion thereof which is farthestfrom the base of said ridge, and a plurality of prick-punches removablyseated in at least some of the sockets projecting a relatively shortdistance from the V-shaped edge of said ridge and substantially lessthan the mentioned minimum thickness of the sheet metal to be bent topierce into a surface of the sheet metal with: out perforating it tohold it securely in predetermined position during the formation of abend therein.

7. A male die for cooperation with a female die to bend sheet metal of acertain minimum over-all thickness, and the like, substantially along astraight line comprising a relatively wide die body having a mountingbase portion, an elongated ridge extending along said body opposite saidbase portion and providing a working face, said ridge. having aplurality of sockets therein extending toward said base portion and saidbody having a plurality of knock-out holes each extending therethroughfrom said base portion to one of the sockets, and a plurality ofprick-punches removably seated in at least some of the socketsprojecting a relatively short distance from the working surface of saidridge and substantially less than the mentioned minimum thickness of thesheet metal to be bent to pierce into a surface of the sheet metalwithout perforating it to hold it securely in predetermined positionduring the formation of a bend therein.

8. A male die for cooperation with a female die to bend sheet metal of acertain minimum over-all thickness, and the like, substantially along astraight line comprising a relatively wide die body having a mountingbase portion, an elongated V-shaped ridge extending along said bodyopposite said base portion and providing a working face. said ridgehaving a plurality of sockets therein extending from its edge towardsaid base portion and said body having a plurality of knock-out holeseach extending therethrough from saidlbase portion to one of thesockets, and a pluralityrof prick-punches removably seated in at leastsome of the sockets projecting a relatively short distance from'the edgeof said V-shaped ridge and substantially less than the mentioned minimumthickness of the sheet metal to be bent to pierce into a surface of thesheet metal without perforating it to hold it securely in predeterminedposition during the formation of a bend therein.

9. A male die for cooperation with a female die to bend sheet metal of acertain minimum over-all thickness, and the like, substantially along astraight line comprising a relatively wide die body having a mountingbase portion,'an elongatedridge extending along said-body opposite saidbase portion and providing a working face, said. ridge having aplurality of sockets therein extending toward said base portion and saidbody having a plurality of knock-out holes each extending therethroughfrom said base portion to one of the sockets, a plurality ofprick-punches removably seated in at least some of the socketsprojecting a relatively short distanc from the Working surface-of saidridge and substantially less than the mentioned minimum thickness of thesheet metal to be bent to pierc'e'into a surfaceof the sheet metalwithout perforating it to hold-it securely in predetermined positionduring the formation of a bend therein, andatleasti one plug removablyseated in each of the sockets having its exposed end contoured similarlyto the contour of the face of said ridge to provide a substantiallyunbroken working surface.

10. Dies for bending sheet material of acertain minimum over-allthickness, and the like, comprising, in combination, a female die-havingan elongated groove in its face, a male die comrising a substantiallysolid relatively unyielding body having a complementary elongated ridgeto cooperate with the groove, and a plurality of localized prick-punchesarranged along the poltion of the ridge which is farthest from the basethereof and projecting from and beyond all portionsof the surface ofsaid ridge toward the deepest portion of the groove in said female die arelatively short distance substantially less than the mentioned minimumthickness of the sheet ma terial to be bent; those portions of thesurface of said ridge intervening said projecting prickpunches beingsubstantially uninterrupted and backed by solid male die body material,said prick-punches thus being adapted to pierce'into a surface of thesheet material without perforating the latter to hold it securely inpredetermined position as the dies are brought together and thus assureaccurate location of a bend.

FRANCIS CRAWFORD, V

